diff --git a/docs/changelog.rst b/docs/changelog.rst
index 8914028ea0..11bdb8aedf 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -12,6 +12,11 @@ Added
 - New ``before_add_examples`` hook. `#571`_
 - New ``after_init_cli_run_handlers`` hook. `#575`_
 
+Fixed
+~~~~~
+
+- Passing ``workers_num`` to ``ThreadPoolRunner`` which lead to always using 2 workers in this worker kind. `#579`_
+
 `1.5.1`_ - 2020-05-08
 ---------------------
 
@@ -1040,6 +1045,7 @@ Fixed
 .. _0.3.0: https://github.com/kiwicom/schemathesis/compare/v0.2.0...v0.3.0
 .. _0.2.0: https://github.com/kiwicom/schemathesis/compare/v0.1.0...v0.2.0
 
+.. _#579: https://github.com/kiwicom/schemathesis/issues/579
 .. _#575: https://github.com/kiwicom/schemathesis/issues/575
 .. _#571: https://github.com/kiwicom/schemathesis/issues/571
 .. _#566: https://github.com/kiwicom/schemathesis/issues/566
diff --git a/src/schemathesis/runner/__init__.py b/src/schemathesis/runner/__init__.py
index 6221898915..a955598316 100644
--- a/src/schemathesis/runner/__init__.py
+++ b/src/schemathesis/runner/__init__.py
@@ -188,6 +188,7 @@ def execute_from_schema(
                     auth_type=auth_type,
                     headers=headers,
                     seed=seed,
+                    workers_num=workers_num,
                     request_timeout=request_timeout,
                     exit_first=exit_first,
                     store_interactions=store_interactions,
diff --git a/test/runner/test_runner.py b/test/runner/test_runner.py
index cf580ba60c..3d976567cb 100644
--- a/test/runner/test_runner.py
+++ b/test/runner/test_runner.py
@@ -15,7 +15,7 @@
 from schemathesis.checks import content_type_conformance, response_schema_conformance, status_code_conformance
 from schemathesis.constants import USER_AGENT
 from schemathesis.models import Status
-from schemathesis.runner import events, get_base_url, get_requests_auth, prepare
+from schemathesis.runner import ThreadPoolRunner, events, get_base_url, get_requests_auth, prepare
 from schemathesis.runner.impl.core import get_wsgi_auth
 
 
@@ -605,3 +605,11 @@ def test_reproduce_code_with_overridden_headers(args, base_url):
     else:
         expected = f"requests.get('{base_url}/api/failure', headers={headers})"
     assert after.result.checks[1].example.requests_code == expected
+
+
+@pytest.mark.endpoints("success")
+def test_workers_num_regression(mocker, schema_url):
+    # GH: 579
+    spy = mocker.patch("schemathesis.runner.ThreadPoolRunner", wraps=ThreadPoolRunner)
+    execute(schema_url, workers_num=5)
+    assert spy.call_args[1]["workers_num"] == 5